This invention relates to a metal mold for producing a wood type golf club head, and more particularly to a metal mold for producing a wood type golf club head which enables a molded product to be removed therefrom easily, and the shaft bore molding accuracy to be improved.
In general, there are two types of well-known metal molds, which are shown in FIGS. 7 and 8, for producing wood type golf club heads out of a raw material, such as a fiber-reinforced plastic. A metal mold 3 shown in FIG. 7, for producing a wood type golf club head consists of upper and lower metal mold members 1, 2, and the upper metal mold member 1 is provided at the portion thereof which corresponds to a hosel of an object club head with a shaft pin 4 so that the shaft pin 4 which is formed integrally with the same mold member and used to form a club shaft fitting bore projects toward a sole of the lower metal mold member 2. However, since the shaft pin 4 in this metal mold 3 inclines greatly from the direction in which the upper and lower metal mold members 1, 2 are opened, it is difficult to remove a molded club head from the metal mold.
In view of the above, a metal mold 3 shown in FIG. 8 has been proposed. In this metal mold 3, a shaft pin 4 is formed independently of an upper metal mold member 1, and, when a molded product is removed from the mold 3, the shaft pin 4 is withdrawn therefrom after the upper metal mold member 1 has been opened, to solve the above-mentioned problem. However, in this metal mold, the position of the shaft pin 4 varies minutely due to the inner pressure thereof, so that the shaft bore positioning accuracy lowers. Especially, in the case of a club head having a short hosel, or, in the case of a no-hosel type club head in which a hosel is not provided at all, the upper end portion of a shaft bore demands a high molding accuracy but it is very difficult to achieve such a high molding accuracy by using this metal mold 3.